The purpose of this project is the conduct of research and analysis on issues related to cancer prevention and control. The emphasis is on analysis of already existing data bases which can provide insight into important problems in cancer control. The specific problems in this area arise from questions which are not answered in the context of current cancer control research, policy questions which are put to the Division, and as spinoffs of other projects under development in the Division. One study ongoing prior to the establishment of the Operations Research Section was a major study of multiple primary cancer in the SEER data base. This study will provide a comprehensive resource of the most recent data on the occurrence of multiple primaries. The linkage of certain cancers related to preventable causes is important for cancer control research. The occurrence of multiple risk factors for cancer is also under study. Using a national probability survey from NCHS, a team of investigators is exploring characteristics related to the prevalence of cancer risk factors. Using the long historical data from the Connecticut Tumor Registry, the prevalence of all major cancer sites is being investigated. This project will not only produce important original research, but also provide an empirical foundation for programmatic decisions concerning cancer survivor studies.